This invention relates to a sheet peeling pawl the top end portion of which is abutted against the surface of a photo-sensitive material or the surface of a fixing roll in an electronic copying machine to peel a sheet off the surface thereof.
In general, a conventional sheet peeling pawl of this type is in the form of a wedge, or some other special configuration, and the conventional sheet peeling pawl must be manufactured with high machining accuracy. Therefore, the manufacturing cost is high, and a high positioning accuracy is required when it is mounted on the copying machine. Furthermore, a conventional sheet peeling device including such a sheet peeling pawl has a number of components which must be adjusted and uses springs and other parts in order to abut against the photo-sensitive material surface or the fixing roll surface under a predetermined pressure. Thus, the conventional sheet peeling device is intricate in construction, and the cost for assembling the device and the cost for mounting it on the machine are considerably high.
One type of peeling pawl is made of a sheet-shaped material of synthetic resin such as polyester or polyethylene which is excellent in wear resistance and is also flexible. The sheet peeling pawl in the form of a sheet, which is bent to abut against the photo-sensitive material or the fixing roll, is obtained by punching from the sheet-shaped material. Therefore, such a peeling pawl can be readily manufactured. Since the peeling pawl can easily bend to abut against the photo-sensitive material surface or the fixing roll surface, it can be brought into contact with the photo-sensitive material or the fixing roll without the need for either high machining accuracy or high mounting accuracy. The peeling pawl can be mounted in the copying machine by securing it to a supporting member near the fixing roll with a two-sided adhesive tape or screws. Thus, this peeling pawl is advantageous in that it can be readily mounted in and removed from the copying machine, and it is considerably simple in construction.
However, the conventional sheet-shaped peeling pawl is disadvantageous in that it is made of a sheet of synthetic resin such as polyester or polyethylene as described above. Therefore, while sheets onto which images have been transferred (hereinafter referred to as "image-transferred sheets") are repeatedly peeled off with the peeling pawl, the top end portion of the peeling pawl quickly deteriorates, as a result of which the peeling pawl then fails to peel off image-transferred sheets. If the thickness of the peeling pawl is increased in order to prevent the deterioration of the top end portion, then it is impossible to positively peel off sheets; that is, the peeling pawl cannot function as required.